Navigating Heart Health: Exploring a New Balloon Treatment for Blocked Arteries

Interventional cardiologists use a procedure called angioplasty, with tiny metal scaffolds called stents, to clear up blocked arteries. Sometimes, however, the treated artery narrows again, causing a setback known as “in-stent restenosis.” 

In the world of heart health, where millions undergo these procedures every year, a recent FDA approval has introduced a new player in the field: the AGENT drug-coated balloon, now approved as the first coronary drug-coated balloon treatment for in-stent restenosis in the United States. 

To shed light on this latest development, we spoke with Ajay Kirtane, MD, SM, Director of Columbia Interventional Cardiovascular Care, and senior author of the Journal of American Medical Association (JAMA) paper examining the new balloon. Dr. Kirtane shared his insights into the significance of the science and the potential impact on heart treatments in the future. 

What is a stent, what is in-stent restenosis, and why does it happen?

A stent that’s placed in the heart artery is basically a metal scaffold that is used to hold the artery open and to push the plaque that’s in the artery to the side. That actually has been a great advancement. 

But one of the problems with a stent is that because it’s a foreign body in the bloodstream, it can cause scar tissue formation within the stent. Especially with the latest stent technologies, this doesn’t happen frequently, but if it does happen, that’s called restenosis. If the restenosis does significantly re-narrow the artery, then patients sometimes need repeat procedures such as repeat stenting or even bypass surgery.

The drug-coated balloon is designed to reduce the need for those types of procedures – because by putting in a drug to treat that locally targets scar tissue formation, the patient may not need another stent, or may not have to do surgery, and hopefully, that will prevent the restenosis from ever coming back again.

How common is in-stent restenosis?

This phenomenon of the stent re-narrowing or restenosis is thankfully pretty uncommon. Currently, it happens less than 10% of the time. But, for patients who have a lot of stents or for patients followed for a significant period of time after their initial stent, restenosis can occur. When it occurs, unfortunately, it requires repeat procedures to treat. The idea behind a drug-coated balloon is that if it does recur - this allows you to treat it without having to put in another stent - and that can actually save a stent procedure for another day if that’s really needed. 

In the studies that we’ve done to lead to approval of this device in the U.S., we found that the rate of repeat re-narrowing was markedly lower with a drug-coated balloon compared to an uncoated balloon.

What are the current standards of care for treating in-stent restenosis?

​​Right now, if you have blockages within a stent, you can put another stent that contains a drug to prevent recurrent scar formation. Sometimes patients go for bypass surgery, and sometimes patients go for radiation therapy. However, the challenge with repeat stenting or bypass surgery is that they either require a big operation or another layer of metal within another layer of metal - and the artery gets smaller and smaller, in a sense.

By using a drug-coated balloon, we can still deliver the drug, but don’t need to leave another layer of metal behind. So, that’s one of the appeals of a drug-coated balloon, which is inflated and then removed without putting another layer of metal.

Can you explain the technology behind the drug-coated balloon?

A drug-coated balloon is a balloon that gets inserted into the heart artery and coated with a drug that stays on the artery wall once the balloon is removed. So, you’re basically using the balloon to snake through the arteries. You blow up the balloon to deliver the drug. Deflate the balloon, take the balloon out, and the only thing that gets left behind is the drug. In a sense, it’s actually better than taking a drug orally because when you take it, it goes all over the body. When you insert the drug into a heart artery, the drug really only goes where you want it to be, where that scar tissue formed after a prior stent.

Are there any potential risks associated with the use of the drug-coated balloon?

The risks associated with a drug-coated balloon are the standard risks associated with an angioplasty procedure. One of the things that we were aware of when we did this study is to make sure the drug doesn’t go downstream in the artery and stays where we want it to be. Compared to an uncoated balloon, there were really no safety differences between the drug-coated balloon and the uncoated balloon. 

Who would benefit the most from using this new balloon treatment? 

The people who would benefit the most from this type of treatment are those who have multiple layers of stents, where you really don’t want to put in another metal layer, which can make the artery smaller and smaller. Also, if people have a first re-narrowing within the stent, and for whatever reason, you do not want to put in another stent, this allows another option to avoid putting in a stent at that time. 

Later, if the patient needs another stent, that could be done with this in between. But, hopefully, that wouldn’t have to happen because when you treat with this specific balloon, you reduce the rate of the patient returning for repeat procedures - which is obviously a good thing.

Where do you see this technology going next? Can it be applied beyond coronary treatment?

It’s great to have this technology approved here in the U.S. It’s been available outside the U.S. for many years. The idea is to not only treat patients with re-narrowed stents but there are some cases where you wouldn’t want to put a stent in a small vessel or at a branch point, for example. Outside of the U.S., these devices are being used for those purposes. Of course, we need to study this usage first in the U.S., and for those purposes; however, an approval like this allows us to start doing those studies, and those studies are already underway.